Ventilator-associated pneumonia and the importance of education of ICU nurses on prevention - Preliminary results.

BACKGROUND AND AIMS: Ventilator-associated pneumonia (VAP) increases intensive care unit (ICU) length of stay, ICU mortality, the number of ventilator days, and costs. We implemented a VAP bundle and investigated its efficacy on prevention.
MATERIALS AND METHODS: A prospective observational study was conducted between January 1, 2015 and December 31, 2015 in a 12-bed multidisciplinary ICU. The bundle was implemented on July 02, 2015. Comparative analysis was performed before and after the implementation of the bundle. The compliance of the nurses was also studied.
RESULTS: The incidence of VAP was 21.5/1,000 ventilator days (95% CI: 14.17-31.10) in the first phase and 12.0/1,000 ventilator days (95% CI: 7.2-19.49) in the second phase. Relative risk reduction was 44% (95% CI: -0.5 to 0.98). Most common bacteria identified during the first phase were Pseudomonas aeruginosa, Stenotrophomonas maltophilia, and Staphylococcus aureus; and in the second phase P. aeruginosa, Acinetobacter baumannii, and S. maltophilia were identified. Significant improvement was achieved in the head-of-bed elevation (p = 0.004), oral care (p = 0.01), hand hygiene (p < 0.001), endotracheal suctioning (p = 0.004), and removal of condensate (p = 0.043). DISCUSSION: The incidence of VAP showed tendency for reduction. The prevalence of nursing-dependent bacteria decreased and compliance in following prevention methods increased.
CONCLUSION: These results underline the importance of education of prevention methods.

Introduction

Ventilator-associated pneumonia (VAP) is defined as a pneumonia occurring over 48 h after endotracheal intubation characterized by new lung infiltrate, new onset of fever, purulent sputum, leukocytosis, and decline in oxygenation [1]. VAP is a frequent complication in critically ill patients and is among the most common hospital-acquired infections [2]. It occurs approximately in 10–20% of patients requiring mechanical ventilation and this rate has not declined over the past years [3, 4]. The incidence of VAP is 14.5 cases per 1,000 ventilator days in Europe [5]. It impacts the patient outcomes negatively, as it is associated with increased mortality, longer length of stay (LOS) intensive care unit (ICU), and higher costs [3, 6–8]. According to the previously published studies, the implementation of a VAP bundle had been proven to be efficacious in reduction of VAP rates [9-11]. Education plays an important role in the prevention of VAP [12, 13]. The importance of alternative methods including positive suggestions was also shown to be effective in reducing days on ventilator [14]. This study examined the changes in the incidence and the bacterial spectrum of VAP after the implementation of a bundle. The compliance of ICU nurses was also studied.

Materials and Methods

Study design

A prospective observational study was conducted between January 1, 2015 and December 31, 2015 in the Department of Anaesthesiology and Intensive Therapy, Semmelweis University, Budapest, Hungary. The study population included all patients treated in the 12-bed multidisciplinary ICU during the given time period without considering the patients’ diagnosis. We identified and enrolled VAP patients according to the definition of VAP by the American Thoracic Society and the Infectious Diseases Society of America [1]. The diagnosis of VAP was set if the patient was intubated over 48 h, new or progressive radiographic infiltrate occurred, along with the clinical findings suggesting infection, which include the new onset of fever, purulent sputum, leukocytosis, and decline in oxygenation. Microbiological studies were performed on endotracheal aspirates and respiratory samples were obtained by bronchoalveolar lavage (BAL). The diagnostic threshold of pathogenic strains was over 105 colony-forming units (CFU)/ml for endotracheal aspiration and 104 CFU/ml for BAL. Our bundle comprised of protocolized humidification, nebulization, and 1-day nurse education. We educated all the ICU nurses on the importance of VAP prevention methods including the head-of-bed elevation, oral care, hand hygiene, cuff pressure control, aseptic endotracheal suctioning technique, and handling of respiratory equipment. The education included a “High-Fidelity” practical simulation on endotracheal suctioning, with common debriefing as well. Compliance with bundle elements was recorded by an infection control practitioner using a checklist based on 100 observations. A comparative analysis was performed before (pre-VAP bundle phase) and after the implementation of the bundle (post-VAP bundle phase). The dividing point was July 02, 2015, when the bundle was implemented.

Statistical analysis

All statistical data were analyzed on SPSS software, version 20.0 (SPSS Inc., Chicago, IL, USA). Baseline characteristics were compared using the χ2 test for categorical variables and the t-test for continuous variables. A p value <0.05 was considered to be statistically significant.

The authors of this manuscript have certified that they comply with the principles of ethical publishing in Interventional Medicine & Applied Science [15].

Results

Demographic characteristics

A total of 535 patients were treated in the ICU during the study period. Of the 535 patients, 275 were from the pre-VAP bundle phase and 260 from the post-VAP bundle phase. Table  shows the demographic characteristics of ICU patients from both phases. There was no significant difference in the number of patients, male/female ratio, mean age, LOS, ventilator days, and case-mix index (CMI). CMI reflects the clinical complexity and severity (resource requirement) in the population of all the patients in the hospital.

Characteristics of VAP patients

Out of the 535 patients, a total of 39 met the inclusion criteria. We registered 24 VAP cases before and 15 VAP cases after the implementation of the bundle. Table  shows the demographic characteristics of VAP patients from both phases. There was no significant difference in the male/female ratio and mean age. The comorbidities of VAP patients and their risk factors for VAP development are shown in Table . Because of the low rate of occurrence of individual alterations, statistical analysis was not performed.

Outcome

After the VAP bundle implementation, incidence of VAP had decreased from 21.5 (95% CI: 14.17–31.10) to 12.0/1,000 ventilator days (95% CI: 7.2–19.49). The relative risk reduction was 44% (95% CI: −0.4 to 0.97) in the post-VAP bundle phase.

Microbiological profile

The changes in the bacterial spectrum of VAP are shown in Figs and. A major fraction of bacteria were multidrug resistant (MDR) in both phases. In the pre-VAP bundle phase, 66% of Pseudomonas aeruginosa, 30% of Stenotrophomonas maltophilia, and 100% of Staphylococcus aureus were MDR bacteria. In the post-VAP bundle phase, 100% of P. aeruginosa, 75% of Acinetobacter baumannii, 50% of S. maltophilia, 50% of Klebsiella pneumoniae, and 100% of S. aureus were MDR bacteria. The rate of VAP caused by P. aeruginosa and S. aureus decreased, while Escherichia coli and Enterobacter cloacae infections disappeared in the post-VAP bundle phase.

Bacterial spectrum before the implementation of the VAP bundle. P. aeruginosa: Pseudomonas aeruginosa; S. maltophilia: Stenotrophomonas maltophilia; S. aureus: Staphylococcus aureus; A. baumannii: Acinetobacter baumannii; K. oxytoca: Klebsiella oxytoca; A. xylosoxidans: Achromobacter xylosoxidans; K. pneumoniae: Klebsiella pneumoniae; S. marcescens: Serratia marcescens; B. multivorans: Burkholderia multivorans; E. cloacae: Enterobacter cloacae; E. coli: Escherichia coli

Bacterial spectrum after the implementation of the VAP bundle. P. aeruginosa: Pseudomonas aeruginosa; A. baumannii: Acinetobacter baumannii; S. maltophilia: Stenotrophomonas maltophilia; K. pneumoniae: Klebsiella pneumoniae; S. aureus: Staphylococcus aureus; B. multivorans: Burkholderia multivorans; K. oxytoca: Klebsiella oxytoca

Compliance with the VAP bundle

The compliance study of ICU nurses showed significant improvement in the following interventions: head-of-bed elevation (p = 0.004), oral care (p = 0.01), hand hygiene (p < 0.001), endotracheal suctioning (p = 0.004), and removing the condensate from circuit (p = 0.043) (Fig. .

Compliance of ICU nurses in prevention methods before and after the implementation of the VAP bundle

Discussion

VAP cases are potentially preventable and ventilator bundles are effective to reduce the VAP rates [9–11, 16, 17]. We initiated a bundle for prevention and education on VAP for the first time in our department. This study demonstrates a reduction in the incidence and risk of VAP after the implementation of the bundle. The same trend was observed in a multicenter study by Eom et al. [9], where the incidence of VAP decreased from 4.08 to 1.16/1,000 ventilator days. However, the post-bundle phase was shorter and the number of ventilator days was lower (4 months and 6,025 ventilator days compared with 8 months and 13,937 ventilator days), and the significantly lower prevalence of VAP suggests a substantially different study environment. The bundle elements were head-of-bed elevation, peptic ulcer prophylaxis, deep venous thrombosis prophylaxis, and oral decontamination. Lim et al. [11] used a modified bundle in a surgical ICU. The incidence of VAP decreased from 13.63 to 3.94/1,000 ventilator days, although the number of ventilator days was significantly lower in the post-bundle phase.

Regarding our VAP bundle, the nurse education played an important role and we could observe a significant improvement in prevention methods. An outstanding improvement was found in hand hygiene of ICU nurses. This rate (91%) is even higher compared with the results of Lambert et al. [18], where they described a compliance rate of 57% on hand hygiene recommendations. The recently published Greek study by Parisi et al. [19] also highlighted the importance of staff education on VAP prevention. They implemented a longer educational program of 3 months every 2 weeks and the compliance of ICU staff was also controlled. Decreased incidence rate (from 21.6 to 11.6/1,000 ventilator days), shorter mean ICU LOS (from 36 to 27 days), and lower number of ventilator days (from 26 to 21 days) were observed after the education. Viana et al. [13] introduced an educational module about VAP and used a bundle checklist in a Brazil study. The mean VAP rate before the intervention was 18.6 ± 7.8/1,000 ventilator days, decreasing to 11.8 ± 7.8/1,000 ventilator days after the intervention.

The major determinant of VAP development is the presence of the endotracheal tube and oropharyngeal colonization from endogenous and exogenous sources as well [20], thus acquiring VAP might be not only “ventilator associated.” Nurses play an important role in preventing bacterial colonization of mechanically ventilated patients. Many of the prevention methods of VAP are a part of routine nursing care [21]. The altered microbiological profile may refer to a better compliance in hand hygiene, oral care, aseptic endotracheal suctioning technique, and handling of respiratory equipments. In the literature, we found no data about the changes in the bacterial spectrum of VAP after the initiation of a bundle. The observation of the microbiological profile of VAP is also a part of the infection control surveillance and can help in the development of proper prevention strategies and choosing empirical antibiotic therapy.

This study had some limitations. First, the number of enrolled patients was relatively low compared with previous studies. However, we could observe a decline in the incidence of VAP correspondingly to European epidemiologic data. Second, our results were limited to a multidisciplinary ICU of a single center. In the future, we are planning to expand this VAP bundle in more ICUs.

To our knowledge, this is the first study in Hungary that investigated the efficacy of a bundle on prevention and incidence of VAP.

In conclusion, this VAP bundle proved to be effective in reducing the incidence of VAP. This result also highlights the importance of education in more ICUs.

Authors’ contribution

BM recorded and analyzed the clinical data and contributed to the statistical analysis and manuscript production. ED recorded the clinical data. JG reviewed the manuscript. ZsI designed the study, enrolled patients, and approved the final manuscript. All authors had full access to all the data in the study and take responsibility for the integrity of the data and the accuracy of the data analysis.

Conflict of interest

The authors declare that they have no conflict of interest.

Table I

Demographic characteristics of patients before and after the implementation of the VAP bundle

	Before the implementation of the VAP bundle	After the implementation of the VAP bundle	p value
Number of patients	275	260	0.66
Male/female ratio	132/143	133/127	0.47
Mean age (SD)	69.75 years (14.32)	68.74 years (14.04)	0.41
Length of ICU stay (days)	1,833	1,814	0.79
Days on ventilator	1,117	1,249	0.08
Case-mix index	6.13	6.53	0.42

Table II

Characteristics of VAP patients before and after the implementation of the VAP bundle

	Before the implementation of the VAP bundle	After the implementation of the VAP bundle	p value
Number of VAP cases	24	15	–
Incidence of VAP (cases/1,000 ventilator days)	21.5 (95% CI: 14.17–31.10)	12.0 (95% CI: 7.2–19.49)	–
Male/female ratio	14/10	9/6	0.918
Mean age (SD)	73.25 years (9.65)	68.6 years (16.48)	0.272

Table III

Comorbidities of VAP patients and their risk factors for VAP development before and after the implementation of the VAP bundle

	Before the implementation of the VAP bundle (number of cases)	After the implementation of the VAP bundle (number of cases)
Chronic lung  disease	5	3
Hypertension	18	10
Diabetes mellitus	7	5
Gastroesophageal  reflux disease	4	0
Acute respiratory  distress syndrome	3	0
Aspiration	2	2
Reintubation	4	7
Immunosuppression	3	4
Previous antibiotic  exposure	5	7
Renal replacement  therapy	3	2
Chest surgery	1	1
Abdominal surgery	7	5
Coma	4	0
Head trauma	1	0
Dementia	2	2